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Comparative roles of upwelling and glacial iron sources in Ryder Bay, coastal western Antarctic Peninsula

Comparative roles of upwelling and glacial iron sources in Ryder Bay, coastal western Antarctic Peninsula
Comparative roles of upwelling and glacial iron sources in Ryder Bay, coastal western Antarctic Peninsula
Iron (Fe) is an essential micronutrient for phytoplankton, and is scarce in many regions including the open Southern Ocean. The western Antarctic Peninsula (WAP), an important source region of Fe to the wider Southern Ocean, is also the fastest warming region of the southern hemisphere. The relative importance of glacial versus marine Fe sources is currently poorly constrained, hindering projections of how changing oceanic circulation, productivity, and glacial dynamics may affect the balance of Fe sources in this region.

Dissolved and total dissolvable Fe concentrations were measured throughout the summer bloom period at a coastal site on the WAP. Iron inputs to the surface mixed layer in early summer were strongly correlated with meteoric meltwater from glaciers and precipitation. A significant source of Fe from underlying waters was also identified, with dissolved Fe concentrations of up to 9.5 nM at 200 m depth. These two primary Fe sources act on different timescales, with glacial sources supplying Fe during the warm summer growing period, and deep water replenishing Fe over annual periods via deep winter mixing.

Iron supply from deep water is sufficient to meet biological demand relative to macronutrient supply, making Fe limitation unlikely in this area even without additional summer Fe inputs from glacial sources. Both glacial and deep-water Fe sources may increase with continued climate warming, potentially enhancing the role of the WAP as an Fe source to offshore waters.
Iron, aluminium, iron budget, glacial input, upwelling, Ryder Bay
0304-4203
21-33
Annett, Amber L.
de404d72-7e90-4dbd-884a-1df813808276
Skiba, Marta
3711d3ac-805d-48fc-b4a8-f92467d375ca
Henley, Sian F.
cd7c7f77-8494-46ad-98a9-08907fa6e06b
Venables, Hugh J.
076cfe85-e2f9-4e69-8793-0ab225e7fadd
Meredith, Michael P.
25fd5f1c-f3ed-40a2-af59-5a7074a25fcd
Statham, Peter J.
51458f15-d6e2-4231-8bba-d0567f9e440c
Ganeshram, Raja S.
108fdc69-5502-4b6f-922f-dd12b398e267
Annett, Amber L.
de404d72-7e90-4dbd-884a-1df813808276
Skiba, Marta
3711d3ac-805d-48fc-b4a8-f92467d375ca
Henley, Sian F.
cd7c7f77-8494-46ad-98a9-08907fa6e06b
Venables, Hugh J.
076cfe85-e2f9-4e69-8793-0ab225e7fadd
Meredith, Michael P.
25fd5f1c-f3ed-40a2-af59-5a7074a25fcd
Statham, Peter J.
51458f15-d6e2-4231-8bba-d0567f9e440c
Ganeshram, Raja S.
108fdc69-5502-4b6f-922f-dd12b398e267

Annett, Amber L., Skiba, Marta, Henley, Sian F., Venables, Hugh J., Meredith, Michael P., Statham, Peter J. and Ganeshram, Raja S. (2015) Comparative roles of upwelling and glacial iron sources in Ryder Bay, coastal western Antarctic Peninsula. Marine Chemistry, 176, 21-33. (doi:10.1016/j.marchem.2015.06.017).

Record type: Article

Abstract

Iron (Fe) is an essential micronutrient for phytoplankton, and is scarce in many regions including the open Southern Ocean. The western Antarctic Peninsula (WAP), an important source region of Fe to the wider Southern Ocean, is also the fastest warming region of the southern hemisphere. The relative importance of glacial versus marine Fe sources is currently poorly constrained, hindering projections of how changing oceanic circulation, productivity, and glacial dynamics may affect the balance of Fe sources in this region.

Dissolved and total dissolvable Fe concentrations were measured throughout the summer bloom period at a coastal site on the WAP. Iron inputs to the surface mixed layer in early summer were strongly correlated with meteoric meltwater from glaciers and precipitation. A significant source of Fe from underlying waters was also identified, with dissolved Fe concentrations of up to 9.5 nM at 200 m depth. These two primary Fe sources act on different timescales, with glacial sources supplying Fe during the warm summer growing period, and deep water replenishing Fe over annual periods via deep winter mixing.

Iron supply from deep water is sufficient to meet biological demand relative to macronutrient supply, making Fe limitation unlikely in this area even without additional summer Fe inputs from glacial sources. Both glacial and deep-water Fe sources may increase with continued climate warming, potentially enhancing the role of the WAP as an Fe source to offshore waters.

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More information

e-pub ahead of print date: 27 June 2015
Published date: 20 November 2015
Keywords: Iron, aluminium, iron budget, glacial input, upwelling, Ryder Bay
Organisations: Ocean and Earth Science, Marine Biogeochemistry

Identifiers

Local EPrints ID: 378899
URI: https://eprints.soton.ac.uk/id/eprint/378899
ISSN: 0304-4203
PURE UUID: d4da7df9-6268-4751-bd1c-58c2a3e2a5b2
ORCID for Amber L. Annett: ORCID iD orcid.org/0000-0002-3730-2438

Catalogue record

Date deposited: 09 Jul 2015 12:10
Last modified: 06 Jun 2018 12:12

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